The present invention relates generally to textile cords and more specifically to cords for reinforcing belts, overlays, bead portions and carcasses of tires. The invention discloses further a method for making such cords and a tire including such cords.
Reinforcement cords currently used in tires are composed of one or several yarns consisting of fibers of textile material such as nylon, polyester and rayon, such reinforcement having a linear yarn density of 1,000 to 9,000 Denier. The yarns and the cord are respectively twisted from about 6 TPI to about 12 TPI. Such multifilament cords are cheap to manufacture and easy to treat. The drawbacks of these cords are that they are soft, have a low tenacity and historically were developed to optimize carcass fatigue resistance in bias ply tires.
It is also known in the tire art to use polyamide monofilaments, such as HYTEN.RTM., or monofilaments of polyester, to reinforce tire components, such as chafers and chippers. The monofilament cords may have exceptional tenacity, providing strength levels which cannot be attained in comparable twisted cords. Unfortunately these cords are expensive and can lead to tire building problems due to their high stiffness. Furthermore they offer a reduced surface for bonding to rubber.